The known runway lights are constituted of an embedded seating, of a lid fixed on the base with generally an integrated uni- or bi-directional prism, and of an optical unit containing in particular the lamp.
Replacement of the lamp or of the colored filter in such lights (i.e. relatively frequent maintenance operations), requires the removal of a large number of screws and the lifting up of a very heavy assembly consisting of the lid and of the optical unit (which, being partly made of steel, can weigh between 8 and 9 kg): this, moreover, exposing the sealed off base member to a risk of penetration of foreign matter (such as water, dust, stones, . . . ) which increases with the size of the uncovered surface, and which can affect tightness preservation during re-assembling.
It has been proposed to make the optical unit removable independently of the lid, through an opening in the center of said lid, but its removal in this way is very difficult and requires the use of particularly adapted instruments as well as the creation of "holds" on the optical unit since, in its working position, said unit should be on the same upper level as the lid and therefore is not easy to grasp. Such "holds" form bumps on the surface of the runways, which bumps are damaging to the tyres of aircraft being wheeled over them.